Circuit breaker



March 26, 1940. R. H. swlNGLE CIRCUIT BREAK Filed April .7, 1937 3 Sheets-Sheet 2 INVENTOR /Fzyf/@Q/f,

ATTORNE WITNVESSES:

March 26, 1940. R. H. swlNGlLE CIRCUIT BREAKER med April 7, l1937 3 sheets-sheet 5 WITNESSES:

Patented Mar. 26,1940

UNITED STATES PATENT OFFICE Westinghouse Electric Manuiac Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application April 7, 1937, Serial No. 135,475

31 Claims.

The invention relates to electrical control devices in general and more particularly to circuit breakers for controlling electric lighting and power distribution feeder systems.

An object of the invention is the provision of a circuit breaker embodying an improved operating mechanism which is manually operable to open or to close the contacts of the breaker with a snap action, and which is automatically operable to trip the contacts open in response to predetermined abnormal conditions irrespective of the position of the manual control handle.

Another object of the invention is the provision of a circuit breaker embodying an improved operating mechanism for manually opening or closing the contacts of the breaker with a snap action, for automatically tripping the contacts open in response to predetermined abnormal conditions irrespective of the position of the manual control handle, and which automatically resets itself following each tripping operation.

Another object of the invention is the provision of a circuit breaker embodying an improved operating mechanism of the character described, whichv is simple, emcient and reliable in operation, and which is inexpensive to manufacture.

'I'he novel features that are considered characteristic of the invention are set forth in particularin the appended claims. 'I'he invention, itself, however, both as to structure and operation, together with additional objects and advantages thereof, will best be understood from the following detailed description of several embodiments thereof when read in connection with the accompanying drawings, in which:

Figure 1 is a vertical sectional View of a singlepole circuit breaker embodying the features of my invention, the breaker being shown in the closed circuit position;

Fig. 2 is a view similar to Fig. 1 showing the relative positions of the parts when the breaker is in the full open position;

Fig. 3 is a view similar to Fig. 1 showing the relative positions of the parts during theA first part of a tripping operation;

Fig. 4 is a fragmentary perspective of a portion of the circuit breaker illustrating certain structural details of the operatingmechanism;

Fig. 5 is a fragmentary perspective view of aY multi-pole circuit breaker embodying the features of my invention;

Fig. 6 is a fragmentary side elevational view of' a portion of the common operating mechanism of the multi-pole circuit breaker shown in Fig.- 5;

Fig. 7 is a vertical sectional view of the multi- (Cl. 20D-116) Fig. 8 is a vertical sectional view similar to Fig.

`'I showing the relative position of the parts during the rst part of a tripping operation.

Referring to Figs. 1 through 4, the single-pole circuit breaker illustrated comprises in general a base 'I of molded insulating material, end terminals 3 and II mounted at opposite ends of the base, a stationary contact I3, a pivoted switch member I5 carrying a movable contact Il for cooperating with the stationary contact, operating mechanism indicated generally at I9, and a cover 2i also of molded insulating material removably secured to the base 'l.

The terminals 3 and II are each provided with an oil'set inner end portion having a screwthreaded opening for receiving screws 23 which pass through the bottom of the base 'I and clamp the terminals in mounted position on the base. 'I'he outer ends of the terminals 0 and II kare provided with screw-threaded openings. for receiving terminal screws for connecting the breaker in an electrical circuit.

'Ihe stationary contact I3 is secured to the off set inner end of the terminal 9 by means of the screw 23 which engages a threaded opening provided in the bottom of the stationary contact I3.

A U-shaped main frame 21 is secured in a recess provided in the base lI by means of a pair of screws 29. The frame 2l provides a support for the elements of the operating mechanism and for the switch member I5.

The switch member I5 comprises a channel member 3| of metallic material having a pair of parallel sides 33, each provided with a longitudinal slot 35. The switch member I5 is pivotally mounted on the main frame through the agency of a pivot pin 3l. A strip 39 of resilient material, preferably spring steel, has one end secured to the underside of the bifurcated switch member in any suitable manner. The free end of the spring strip 39 has the movable contact I1 secured thereto 'by means of a pair of rivets 4I. The body portion of the strip 39 is provided with a centrally located longitudinal slot 43.

A U -shaped trip element 44 of bimetallic material is secured for movement with the switch member 3i by means of rivets I5. The trip element 44 is spaced from the switch member by means of spacers 41 of insulating material, the

spacers 41 and to the switch member 3|. One end of the bimetallic trip'element is electrically rivets l5 serving to clamp the ends of the legs of the trip element 4I between the insulating connected to the spring strip 33 and movable contact I1 through the agency of one of the rivets 45. The other end of the bimetalic trip element 44 is insulated from the strip 39 and the movable contact I1 byfmeans oi an insulating sleeve 43 (Fig. 2) surrounding the rivet 45 which clamps this end of the birnetal trip element to the switch member 3I. The insulated end of the bimetallic trip element is electrically connected to the terminal II through the agency of a nexible shunt conductor 49.

The internal circuit of the breaker extends from the terminal 9 to the stationary contact I3, movable contact I1, spring strip 39, through the bimetallic trip element 44 and the flexible shunt 49 to the other terminal I I.

The operating mechanism for the circuit breaker comprises in general an operating handle 5I of insulating material, a bifurcated operating member 52, a pair of toggle links 53 and 55, and an overcenter spring 51. The operating handle 5I has a portion which projects through an opening 59 provided in the cover 2l. The bifurcated operating member 52 has its bight portion secured to the underside of the operating member 5I and the lower ends of its legs pivotally supported to the side walls of the main frame 21 through the agency of pivot pins EI. The upper ends of the side walls of the main frame 21 are notched and outwardly offset so that the edges 53 and 55 of the offset notched portions form sto'ps for limiting the movement o f the operating handle 5I and member 52. The side walls of the frame are also provided with a pair of inwardly offset projections 61 to form a pivotal support for the upper toggle links 53. The upper pair of toggle links 53 are pivotally supported by means of pivot pins 69 to the inwardly oilset projections 61, so that they are disposed between the legs of the bifurcated operating member 52. The lower toggle link 55 is pivotally connected to the lower ends of the upper toggle links 53 through the agency of a knee pivot pin 1I. The lower end of the toggle link 55 is provided with a pin 13 having a roller 14 which is slidably engagedl in the slots 35 in the legs 33 of the switch member 3I. The lower end of the toggle link 55 is provided with a depending proiection 15 which passes through the slot 43 in the contact supporting strip 33 and is adapted to be engaged and held in latched position by the bight portion of the U-shaped bimetallic trip element 44, as shown in Fig. 1. The bimetallic trip element 44 thus normally holds the lower end of the toggle link 55 in an operative position with its pin 13 at the right-hand end of the slots 35. An overcenter spring 51 is connected in tension between the bight portion oi thevbifurcated operating member 52 and the knee pivot pin 1l. A roller 19 is rotatably mounted between the side walls of the main frame 21 by means of a pivot pin 8l. The roller 19 is disposed below the knee pivot pin 1I, and functions to prevent movement of the toggle links more than a small distance past toggle or extended position, and also to cooperate with the pin and slot connection of the toggle link 55 with the switch member 3l to effect movement of the toggle links topollapsed position upon release of the proiection 15 by the bimetallic trip element 44 in a manner which will hereinafter be described. The switch member 3| is biased toward open circuit position by means of a coil spring 85.

The operation oi the circuit breaker is as follows: With the breaker in closed circuit position (Fig. l), let it be assumed that it is desired to manually open the contacts of the breaker. The operating member 52 is moved in a clockwise direction about its pivot axis 5I by means of the handle 5I. At a predetermined point in the clockwise movement of the operating member 52, the line oi' action of the overcenter spring 51 passes to the right of the pivot pin 69. At this point the force exerted by the overcenter spring 51 moves the toggle links 53 and 55 with increasing acceleration to their collapsed position as shown in Fig. 2. 'I'he movement of the toggle links-53 and 55 to collapsed position efiects rotation of the switch member 3I in a clockwise direction about its pivot pin 31 to the open circuit position with a snap action. The clockwise movement of the switch member 3I is limited by the engagement of the sides 33 of the switch member with the roller 19.`

To close the breaker, the operating member 52 is moved in a counter-clockwise direction about its pivot axis 6I. At a predetermined point in the counter-clockwise movement' of the operating member 52, the line of action oi' the overcenter spring passes to the left of the pivot point 69. At this point the force exerted by the overcenter spring 51 moves the toggle links 53 and 55 to their extended or in toggle position with a snap action. The movement of the toggle links 53 and 55 to their extended or in toggle position moves the switch member 3I in a counter-clockwise direction about its pivot pin 31 to the closed circuit position with a snap action.

The bimetallic trip element 44 normally maintains an operative connection between tite lower end of the toggle link 55 and the switch member 3I, and moves with the switch member during operation of the breaker. The toggle links 53 and 55 when in their extended or in toggle position lock the movable contact l1 in engagement with the stationary contact I3 so as to prevent movement of the switch member 3l to open circuit position. The toggle links when in extended position also maintain a high pressure contact between the movable contact I1 and the stationary contact I3.

With the circuit breaker in the closed circuit position, if an overload of predetermined magnitude and duration occurs in the circuit controlled by the breaker, the heat produced in the bimetallic trip element causes the same to flex in a direction away from the switch member 3| so that the bight portion of the U-shaped trip element disengages the depending projection 15 of the lower toggle link 55. When the lower toggle link is thus released, the resiliency of the spring contact strip 33 and the biasing action of the spring 35 causes the switch member 3l to move in a clockwise direction about its pivot pin 31 toward open circuit position. This movement of the switch member causes the roller 14 to slide toward the left-hand end of the slots 35, as shown in Fig. 3. During the movement of the roller 14 the lower toggle link 55 pivots about and slides on the roller 13 so as to move the toggle links toward their collapsed position causing opening of the circuit even though handle 5I may be held in closed position. At a predetermined point in the movement of the toggle links toward collapsed position, the line of action of the overcenter spring 51 passes to the right of the pivot pin 3|. At this point the force exerted by the overcenter spring 51 moves the operating member 52, if the handle 5I is not held closed, in a clockwise direction about its pivot axis 9| to open position. As the handle moves to open position, the line of action of spring 51 crosses pivot 99 and a component of the force exerted by the overcenter spring 51 pulls the lower toggle link 55-to the right so as to move the pin 13 to its normal position at the right-hand end of the slots 35. When the bimetallic trip element 49 cools, the bight portion thereof reengages over the depending projection 15 of the toggle link 55 to reestablish the operative connection between the toggle link 55 and the switch member 3|. It will thus be seen that the breaker automatically resets itself following each tripping operation, and to close the breaker after a tripping operation it is only necessary to move the handle to the closed position in the ynormal manner.

A multi-pole circuit breaker embodying the features of the invention is shown in Figs. 5, 6, 'I and 8. The terminal structure, the main frame. the operating handle, the toggle links and the over-center spring for the multi-pole breaker are of the same general structure as the corresponding elements of the single-pole breaker previously described and shown in Figs. 1 through 4, and hence the same reference characters have been used to designate the corresponding parts wherever applicable.

'I'he multi-pole breaker includes a plurality of stationary contacts 9| and a plurality of cooperating spaced switch arms 93. 'Ihe switch arms 93 are pivotally mounted on a shaft 95 of insulating material which extends transversely across all of the poles of the breaker. The shaft 95 is pivotally supported by means'of the main frame 21 and a pair of end brackets 91. y

'I'he switch arms 93 are secured for simultaneous movement together to open and to closed circuit position by means of an insulating tiebar 99 which extends transversely across all of the poles of the breaker and passes through openings provided therefor in each of the switch arms 93. The main frame 21 of the breaker is provided with an'enlarged opening for accommodating and permitting movement of the tie-bar 99 during `operation of the breaker. I'he interconnected switch arms 93 are biased in a clockwise direction about the shaft 95 toward their open circuit position by means of a plurality of coil springs |9| interposed between the underside of the switch arms and the base 1 of the breaker.

'I'he single common operating means for the breaker includes an operating handle 5|, an operating member 52, a pair of toggle links 53 and 55 and an overcenter spring 51 of the same 'construction and mounting as the corresponding 'elements shown in Figs. 1 through 4` and described in connection therewith. The central i switch arm 93 is of the same general construction as the switch member 3| shown in Figs. l through 4 with the exception that a pivoted latch |93 is substituted for the bimetallic trip element latch 99 shown in. Figs. l through 4. 'I'he latch |93 I is pivotally mounted on the side of the central switch arm 93 by means of a pivot pin |95, and is biased in a clockwise direction towards latching position by means of a coil spring |91. The hook nose |99 of the latch is adapted to engage and hold the depending projection-15' of the lower toggle link 55 of the operating'mechanism to normally maintain an operative connection between the toggle links of the operating mechanism and the central switch arm 93. The latch |93 normally maintains the pin 13 and roller 14 carried by the lower end of the toggle link 55 in the right-hand end of the slots 35 provided in the sides of the central switch arm 93, as shown in Figs. 5, 6 and 7.

The rotatably mounted shaft 95 constitutes a trip bar for the circuit breaker and has secured thereto, in spaced relation, a plurality of cam members I, one for each switch arm 93, each mounted on the shaft 95 adjacent its corresponding switch ann.

Each of the cams is provided with a projecting vportion ||3 adapted to be engaged by wise rotation of the shaft 95 is limited by a projection |23 carried by the shaft 95 which engages a stop pin |25 projecting from the side wall of the main frame 21. The spring |2| biases the trip shaft 95 to the normal inoperative position shown in Figs. 5 and 6.

A plurality of bimetallic trip elements H5, one for each pole of the breaker, have their upper ends secured in any .suitable manner to the base of the breaker as by means of the screws ||5 to a transverse rib i|9 formed integral with the base 1. 'Ihe lower free ends of the bimetallic trip elements ||5 extend to a position adjacent the projections ||3,of their corresponding cams the trip elements being disposed so that when heated a predetermined amount they flex toward the operating mechanism to effect clockwise rotation of the shaft 95 to a tripping position to trip the breaker.

Each of the trip elements ||5 is connected in circuit with its corresponding switch arm 93 and end terminal by means of the flexible shunts |29 and |22.

The circuit foreach po1eof the breaker ex' tends from one end terminal 9 to the stationary contact 9|, through the switch arm 93, through a flexible shunt |29 rto the free end of thev bimetallic trip element ||5 and through the trip element to the opposite end terminal of the pole of the breaker.

The operation of the circuit breaker is substantially the same as the operation of the singlepole circuit breaker described in connection with Figs. 1 ,through 4, inclusive. The breaker may be manually opened and closed by moving the operating handle thereof to the open or closed position. The movement of the operating handle to the closed position effects simultaneous movement of all of the switch arms 93 to their closed position with a snap action by movement of the toggle links to their extended orl in toggle position. 'Ihe movement of the operating handle to the open position effects `simultaneous ,movement of the switch arms 93 to their open position with a snap action by collapsing the toggle links.

If an overload of predetermined magnitude and duration occurs in the circuits of any of thepoles of the breaker, the bimetallictripe/lement ||5 of that particular pole is heatedfsif flciently to'flex in a direction toward the operating mechanism. The flexing movement of any "one of the trip elements causes the free end thereof to engage and move its correspondingcam member to effect clockwise rotation of the trip shaft 95. The clockwise rotation of the shaft 95 causes the cam nose Ill of the central cam member lll to move the latch |03 in a counter-clockwise direction about its pivot pin |05 to disengage the hook nose |09 from engagement with the depending projection l5 of the lower toggle link 55. When the operative connection of the lower toggle link 55 to the central switch arm 93 is released, the biasing actionof the springs lOl move the switch arms 93 in a clockwise direction toward open position. This movement of the switch arms causes the pin 'I3 and the roller 'I4 to move toward the left-hand end of the slots 35 in the central switch arm 93. During this movement of the pin the lower toggl@ link 55 pivots aboutits roller stop 'I9 to throw the knee of the toggle over-center. As the toggle thus moves toward collapsed position, the force exerted by the overoenter spring moves the operating handle to the full open position and draws the lower end of the toggle link 55 to the right so as to reengage the depending projection l5 thereof with the hook nose |09 of the latch |03. The nose |09 of the latch is cammed to permit the depending projection 'l5' to ride thereover and reengage under the hook portion. It will thus be seen that the breaker .operating mechanism is automatically reset following each tripping operation so that to reclose the breaker it is only necessary to move the operating handle in the normal manner to closed position.

The invention provides a circuit breaker structure embodying a simple operating mechanism which secures quick make and break action of the contacts and which automatically resets itself following each tripping operation. The structure also provides desirable trip-free action so that the contacts may be tripped open even if the operating handle is held in the closed position. A

While the invention has been shown and described specically in accordance with the provisions of the patent statutes, it is obvious that various changes in the structural details thereof may be made without departing from the spirit of the'invention. It is desired, therefore, that the invention be limited only by the reasonableI construction of the appended claims and by the prior art.

I claim as my invention:

1. In a circuit breaker, a switch member movable to open and to closed circuit position, operating means for moving said switch member to open and to.closed circuit position with a snap action comprising an operating handle movable to open or to closed position, a toggle pivoted at one end to a fixed support and having a normally operative releasable and resettable connection to said switch member at its other end, an overcenter spring connecting said handle to the knee of said toggle, electro-responsive means oper- .able' in response to predetermined conditions for releasing said operative connection to cause said operating mechanism to move said switch member to open circuit position.

2. In a circuit breaker, a switch member movable to open and to closed circuit position, operating means for moving said switch member to open and to closed circuit position with a snap action comprising an operating handle movable to open or to closed position, a pair of links forming a toggle pivoted at`one end to a fixed support and` having a normally operative releasable and resettable connection to said switch member at its other end, an overcenter spring connecting said handle to the knee -of said toggle, electroresponsive means operable in response to predetermined conditions for releasing said operative connection to cause said operating mechanism to move said switch member to open circuit position irrespective of the position of said operating handle.

3. In a circuit breaker, a switch member movable to open and to closed circuit position, operating means for moving said switch member to open and to closed circuit position with a snap action comprising an operating handle movable to open or to closed position, a toggle pivoted at one end to a xed support and having a normally operative releasable and resettable connection to said switch member at its other end, an overcenter spring connecting said handle to the knee of said toggle, electro-responsive means operable in response to predetermined conditions for releasing said operative connection to cause said operating mechanism to move said switch member to open circuit position, and reset said operative connection.

4. In a circuit breaker, a switch member movable to open and to closed circuit position, operating means for moving said switch member to open and to closed circuit position with a snap action comprising an operating handle movable to open or to closed position, a pair of toggle links forming a toggle pivoted at one end to a fixed support and having a normally operative releasable and resettable connection to said switch member at its other end, an overcenter spring connecting said handle to the knee ol said toggle, electro-responsive means operable in response to predetermined conditions for releasing said operative connection toy cause said operating mechanism to move said switch member to open circuit position, to move said operating handle to open position, and to reset said operative connection.

5. In a circuit breaker, a switch arm movable to open or to closed circuit position, operating means for moving said arm to open or to closed circuit position with a snap action comprising an operating handle movable to open or closed p0- sition, a pair of links forming a toggle pivoted to a fixed support at one end and having a normally operative releasable and resettable connection at its other end to said arm, an overcenter spring connecting said handle to the kneof said toggle, a latch normally maintaining said operative connection, a bimetallic trip element` operable in response to predetermined conditions for moving said latch to release said operative connection causing said operating means move said switch arm to open circuit position, said operating handle to open position, and/ to reset said operative connection.

6. In a circuit breaker, a stationary contact, a cooperating pivoted switch arm movable to open or to closed circuit position, means biasing said switch arm to open circuit position, operating means for moving said switch arm to open and to closed circuit position with a snap action comprising an operating handle movable to open and to closed position, a toggle pivoted at one end to a fixed support and having a normally operative releasable and resettable connection at its other end to said arm, said toggle when extended holding said arm in\closed circuit position and when collapsed moving said arm to open circuit position, an overcenter spring connecting said handle and the knee of said toggle, an electroresponsive trip element operable in response to predetermined conditions to release said opentive connection to permit said switch arm to move to open circuit position.

1. In a circuit breaker, a stationary contact, a cooperating pivoted switch arm movable to open or to closed circuit position, means biasing said switch :arm to open circuit position, operating means for moving said switch arm to open and to closed circuit position with a snap action comprising an operating handle movable to open .and to closed position, a toggle pivoted at one end to a iixed support and having a normally operative releasable and resettable connection at its other end to said arm, said toggle when extended holding said arm in closed circuit position and when collapsed moving said arm to open circuit position, an overcenter spring connecting said handle and the knee of said toggle, an electro-responsive trip element operable in response to predetermined conditions to release said operative connection to permit said switch arm to move to open circuit position irrespective of th position oi' said operating handle. Y

8. In a circuit breaker, a pivoted switch actuposition, means biasing said switch actuating arm to open circuit position, operating means for moving said switch actuating arm to open and to closed circuit position with a snap action comprising an operating handle movable to open and to closed position, a toggle pivoted at one end to a ilxed support and having a normally operative releasable and resettable connection at its other end to said arm, said toggle when extended holding said arm in closed circuit position and when collapsed moving said arm to open circuit position, an overcenter spring connecting said handle and the knee of said toggle, an electroresponsive trip element operable in response to predetermined conditions to release said operative connection to permit said switch arm to move to open circuit position, the movement of said switch arm toward open circuit position Iollowing release of said operative connection effecting collapse oi' said toggle to move said operating handle to open position andto reset said operative connection.

9. In a circuit breaker, a switch member movable to open or to closed circuit position, operating means manually operable to move said switch member to open or to closed circuit position with a snap action and automatically operable in response to predetermined conditions to eiIect movement oi' said switch member to open circuit position comprising an operating handle movable to open or closed position, a toggle, and an over- 'center spring connecting said handle with the knee of said toggle, said toggle being pivoted at one end to a fixed support and having a normally operative releasable and resettable connection with said switch member at its other end, and

electro-responsive means operable in response to` said predetermined conditions for releasing said operative connection to etlect said automatic operation.

10. In a circuit breaker, a pivoted switch actuating arm movable to open or to closed circuit position and provided with a longitudinal slot, means biasing said switch actuating arm to open circuit position, operating means for moving said switch actuating arm to open and to closed circuit position with a snap action comprising a pair of links forming a toggle pivoted to a xed support vat one end and having a pin adjacent its other end slidably engaged in said slot, a bimetallic trip element carried by said arm ior normally engaging and holding the last-mentioned end of said toggle to provide a releasable operative connection between said toggle and said arm, said toggle when extended holding said switch actuating arm in closed circuit position and when collapsed moving said switch actuating arm to open circuit position, an operating handle movable to open and closed position and an overcenter spring connecting said handle with the knee of said toggle for moving said toggle to collapsed and extended position, said trip element being operable in response to predetermined conditions to release said operative connection to permit said switch actuating arm to move to open circuit position.

11. In a circuit breaker, a pivoted contact actuating arm movable to open or to closed circuit position and provided with a longitudinal slot, means biasing said contact actuating arm to open circuit position, operating means for moving said contact actuating arm to open and to closed circuit position comprising a toggle piv- ,oted to a iixed support at one end and having ating arm movable to open or to closed circuit a' Pill adjacent its Other end slidably 'engaged in said slot, a bimetallic trip element carried by said arm for normally engaging, and holding the last-mentioned end of said toggleto provide a releasable operative connection between said toggle and said arm, said toggle when extended holding said contact actuating arm in closed circuit position and when collapsed permitting movement of said contact actuating arm to open circuit position, an operating handle movable to open and closed circuit position for moving said toggle to collapsed and extended position, said trip element being operable in response to predetermined conditions to release said operative connection to permit said contact actuating arm to move to open circuit position, a stop for engaging said toggle on the contact actuating arm side of the knee of said toggle in the extended position thereof, the movement of said contact actuating arm toward open circuit position following release o said operative connection eiIecting collapse of said toggle to move said operating handie to open circuit position and to automatically reset said operative connection upon cooling of said bimetallic trip element.

12. In'a circuit breaker, a pivoted switch arm provided with a longitudinal slot and movable to open or to closed circuit position, kmeans biasing said arm to open circuit position, operating means for moving said switch arm to open and to closed circuit position comprising a pair of Ilinks forming a toggle pivoted at one end to a fixed support and having a pin adjacent its other end slidably engaged in said slot, a releasable latch biased to normally engage and hold said lastmentioned end of said toggle with said pin at a predetermined point in said slot to provide a releasable operative connection between said toggle and said arm so that said toggle when extended holds said switcharm in closed circuit position and when collapsed moves said arm to open circuit position, an operating handle movable to open and closed position i'or moving the toggle to collapsed or extended position, a bimetallic trip element operable in response to a predetermined condition for movingsaid latch' to release said toggle and permit/said switch arm to move to open circuit position.

13. In a circuit breaker, a pivoted switch arm provided with a longitudinal slot and movable to open or to closed circuit position, means biasing said arm to open circuit position, operating means for moving said switch arm to open and to closed. circuit position comprising a toggle pivoted at one end to a iixed support and having a pin adjacent its other end slidably engaged in said slot, a releasable latch biased to normally engage and hold said last-mentioned end of said toggle with said pin at a predetermined point in said slot to provide a releasable operative connection between said toggle and said arm so that said toggle when extended holds said switch arm in closed circuit position and when collapsed moves said arm to open circuit position, an operating handle movable to open and closed position for moving the toggle to collapsed or extended position, a bimetallic trip element operable in response to predetermined conditions for moving said latch to vrelease said toggle and permit said switch arm to move to open circuit position, a stop for engaging said toggle on the switch arm side of the knee in the extended position of the toggle, the movement of said switch arm following release of said latch effecting collapse of said toggle to cause movement of said handle to open position and resetting of the end of said toggle in engagement with said latch. A

14. In a multi-pole circuit breaker, a plurality of pivoted switch arms secured for movement together to open and to closed circuit position forming a plurality of poles, means biasing said switch arms to open circuit position, a single operating mechanism for moving said switch arms to open and to closed circuit position with a snap action comprising a toggle pivoted at one end to a xed support and having a normally operative releasable and resettable connection at its other end to one of said switch arms, said toggle when extended holding said switch arms in closed circuit position and when collapsed moving said switch larms to open circuit position, an operating handle movable to open or to closed position and an overcenter spring connecting said handle with the knee of said toggle for moving said toggle to collapsed or extended position, a member pivoted concentrically with said one switch arm and means to cause movement of the last said member about its pivot to release said releasable connection, a plurality of electro-responsive trip elements one for each pole each operable in response to predetermined conditions to efl'ect rotation of the last said member about its pivot to cause release of said releasable connection to permit tsaid switch arms to move to open circuit posiion.

15. In a multi-pole circuit breaker, a plurality of pivoted switch arms secured for movement together to open and to closed circuit position formmg a plurality of poles, means biasing said switch arms to open circuit position, a single operating mechanism for moving said switch arms to open and to closed circuit position with a snap action comprising a toggle pivoted at one end to a xed support and having a normally operative releasable and resettable connection at its other end to one of said switch arms, said toggle when extended holding said switch arms in closed circuit position and when collapsed moving said switch arms to open circuit position, an operating handle movable to open or to closed position and an overcenter spring. connecting said handle with the knee of said toggle for moving said toggle to collapsed or extended position,

a member pivoted concentrically with said one switch arm and means to cause movement of the last said member about its pivot to release said releasable connection, a plurality of electroresponsive trip elements one for each pole each e operable in response to predetermined conditions to eil'ect rotation of the last-said member about its pivot to cause release of said releasable connection to permit said switch arms to move to open circuit position, the movement oi said switch arms toward open circuit position following release of said operative connection eiecting co1- lapse of said toggle to move said handle to open position and to reset said operative connection between said toggle and said switch arm.

16. In a multi-pole circuit breaker, a plurality of pivoted switch arms secured for movement to.- gether to open and to closed circuit posit-ion forming a plurality of poles, one of said arms being provided with a longitudinal slot, means biasing said arms to open circuit position, a single operating means for moving said switch arms to open or to closed circuit position comprising a toggle pivoted at one end to a iixed support and having a pin adjacent its other end slidably engaged in said slot, a releasable latch carried by said arm having the slot normally biased to engage and hold the last-mentioned end of said toggle with said pin at a predetermined point in said slot to provide a normal operative connection between said toggle and said arm 'so that said toggle when extended holds said arms in closed circuit position and when collapsed moves said arms to open circuit position, an operating handle movable to an open and to a closed position for moving the toggle to collapsed or extended position, a trip bar pivoted concentrically with said one arm extending across all the poles of said breaker means to cause rotation of said trip bar to release said releasable latch to allow said switch arms to move to open circuit position.

17. In a multi-pole circuit breaker, a plurality of pivoted switch arms secured for movement together to open and to closed circuit position forming a plurality of poles, one of said arms being provided with 'a longitudinal slot, means biasing said arms to open circuit position, a single operating means for moving said switch arms to open or to closed circuit position comprising a toggle pivoted at one end to a fixed support and having a pin adjacent its other end slidably engaged in said slot, a releasable latch carried by said arm having the slot normally biased to engage and hold the last-mentioned end of said toggle with said pin at a predetermined point in said slot to provide a normal operative connection between said toggle and said arm so that said toggle when extended holds said arms in closed circuit position and when collapsed moves said arms to open circuit position, an operating handle movable to an open and to a closed position and an overcenter spring connecting said handle with the knee of said toggle for moving the toggle to collapsed or extended position, a trip'bar pivoted concentrically with said one arm extending across all the poles of said breaker means to cause rotation of said trip bar to release said releasable latch to allow said switch arms to move to open circuit position, the movement of said switch arms toward open circuit position effecting collapse of said toggle to move said handle to open position and to reset the end of said toggle in engagement with said latch.

18. In a circuit breaker, a switch member movable to open or to closed circuit position to open or to close the circuit through said breaker, actuating mechanism having a releasable operative,

connection with said switch member for moving vsaid switchmember to open or to closed circuit means operable in response to predeterminedl conditions in the circuit for releasing the operative connection between said mechanism and said switch member, said mechanism when said connection is released eiecting movement of said switch member to open circuit position and reestablishing said operative connection between said actuating mechanism and said switch member.

19. In a circuit breaker, a switch member movable to open or to'closed circuit position, means biasing said switch member to open circuit position, operating mechanism including a toggle, an overcenter spring and an operating handle for moving the switch member to open and to closed circuit position with a snap action, said toggle being pivoted to a fixed support at one end and having a releasable and resettable operative connection at its other end to said switch member, electro-responsive means operable in response to predetermined conditions to release said operative connection, said mechanism when said operative connection is released eecting movement.

of said switch member to open circuit position and resetting of said toggle to its operative connection with said switch member.

20. In a circuit breaker. a plurality of contact actuating members pivoted for rotation about a common axis, operating means for the circuit breaker having a releasable connection to said contact actuating members, a trip bar pivoted for rotation about the pivotal axis of said contact actuating members for causing release of said connection, and a plurality of current responsive members each operable to actuate said trip bar.. 21. In a circuit breaker, a switch member mov--v able to open and to closed circuit position, operating mechanism for moving the switch member to open and to closed circuit position comprising a toggle pivoted at one end to a xed support and having a releasable and resettable operative connection at its other end to said switch member, an operatingmember movable to an open and to a closed position, an overcenter spring connecting said operating member and the knee of said toggle, and electro-responsive means operable in response to predetermined conditions to release said operative connection to cause movement of the switch member to open circuit position.

22. In a circuit breaker, a switch member movable to open and to closed circuit position, means biasing said switch member to open circuit position, operating mechanism for moving said switch member to open and to closed circuit position comprising a toggle pivoted at one end to a xed support and having a releasable and resettable operative connection at its other end to said switch member, an operating member movable to open and to closed position, an overcenter spring connecting said operating member to the knee of the toggle and electro-responsive means operable in response to predetermined conditions to release said operative connection, said mechanism when said operative connection is released. eii'ecting movement of the switch member to open circuit position, movement of the operating member to open position, and resetting of said toggle to its operative connection with said switch member.

23. In a circuit interrupter, a contact arm movable to open and to closed circuit position, means biasing said arm to open circuit position, operating mechanism for said arm comprising a toggle to the knee of said toggle, said bimetallic trip arm to open and to closed circuit position 'with pivoted at one end to a iixed support, means releasably connecting the other end of the toggle to said contact arm, a movable operating member, an overcenter spring connecting said operating member to the knee oi' said toggle, and an l open and to closed circuit position comprisingy 16 a toggle pivoted at one end to a iixed Support, j

means including a current responsive trip; ele-l' ment for normally and releasabl connecting the f other end of said toggle to said contact larm, a movable operating handle, and an' overcenter spring connecting said handle tothe knee of said toggle, said trip element being 'operable in response to predetermined condition to5 effect release of said contact arm from sail"x4 toggle to permit movement of said arm to open' circuit position.

25,. In a circuit interrupter, a contact arm. movable to open and to closed circuit position, said arm being biased to open circuit position; operating mechanism for moving said arm to open and to closed circuit position with a snap action comprising a toggle pivoted at one end to a iixed support, means normally effecting an operative connection betweenthe other end of said toggle and said contact arm, a movable operating handle, and an overcenter spring connecting said handle to the knee of said toggle, said connecting means between said toggle and vsaid contact arm including a bimetallic trip element operable in response to predetermined conditions to release the connection between said arm and 'said toggle to cause movement of said contact arm to open circuit position.

26. In a circuit interrupter, a contact arm movable to open and to closed circuit position, 45

said arm being biased to open circuit position,

operating mechanism for moving said contact g' arm to open and to closed circuit position with a snap action comprising a toggle pivoted at one end to a, xed support, means including a bimetallic trip element carried by said contact arm for releasably connecting the other end of said toggle tov said arm, a movabley operating handle, and an overcenter spring connecting said handle element being operable in response to predetermined conditions to release the connection between said arm and said toggle tol permit movement of said contact arm to open circuit position.

27. In a circuit interrupter, a contact arm movable to open and to closed circuit position, said arm being biased to open circuit position, operating mechanism for moving said contact 'the knee of said toggle, and an electric-responsive trip element operable in response to predetermined conditions to cause said latch to release the connection between said contact arm 75 and said toggle to permit movement o! said contact arm to open circuit position.

28. In a circuit 'interrupten a contact arm movable to open and to closed circuit position, a spring biasing said arm to open circuit position, snap acting mechanism for moving said contact arm to open and to closed circuit position with a snap action, means including a latch pivoted on said contact arm for normally and releasably connecting said arm to said snap acting mechanism, and an electroresponsive trip element operable in response to predetermined conditions to cause said latch to release the conncction between said arm and said mechanism to allow said contact arm to move to open circuit position.

29. In a circuit interrupter, a contact carrying arnrmovable to open and to closed circuit position, means biasing said arm to open circuit position, a Contact resiliently mounted on said arm, snap acting mechanism for moving said arm to open and to closed circuit position with a snap action, means normally and releasably connecting said arm to said snap acting mechanism for movement thereby, and a bimetallic trip element operable in response to predetermined conditions to release the connection between said arm and said mechanism to cause movement of said contact arm to open circuit position.

30. In a circuit interrupter, a stationary contact, a rigid contact carrying arm movable to open and to closed circuit position, a contact resiliently mounted on said arm for engaging said stationary contact, means biasing said arm to open circuit position, operating mechanism for moving said arm to open and to closed circuit position with a snap action comprising a toggle pivoted at one end to a ilxed support, means including a bimetallic trip element carried by said arm for normally and releasably connecting the other end of said toggle to said arm, a movableoperating handle, an overcenter spring connecting said handle to the knee oi said toggle, said trip element being operable in response to predetermined condition to release the connection of said arm to said toggle to cause movement of said contact arm to open circuit position.

3l. In a circuit breaker a plurality of simultaneously actuated contact members, at least one of which is mounted on a pivot, operating means for said circuit breaker having a releasable connection to said one contact member, an element pivoted concentrically with said pivoted contact member, means for causing rotation of said element about its pivot to release said releasable connection, and current responsive means for causing rotation of said element about its pivot in response to predetermined current conditions in the circuit controlled by said circuit breaker.

RALPH H. SWINGLE. 

